LoLSkinshop and other sites like it were essentially closed down by Riot expiring all unredeemed codes before a certain date because too many third party sites would take your money and not give you the skin. Third party sources for skins are unreliable at best, a blatant scam at worst. Just take comfort in the fact that the old skins you can no longer get are usually well below average skin quality
On a completely different note, 40 minutes until TSM v C9. I've heard that C9 lost a lot of recent scrims against TSM, so this could be interesting for once.